1. Field of the Invention
The present invention relates to a color filter for use in a liquid crystal display, and, more particularly, to a color filter capable of providing excellent halftone color reproducibility and a liquid crystal display comprising the same.
2. Background Art
Liquid crystal displays have so far been used mainly as personal computer monitors. In recent years, they have rapidly come to be used also as television monitors.
In the meantime, when liquid crystal displays are used as television monitors, they are used in dark environments more often as compared with the case where liquid crystal displays are used as personal computer monitors. Further, it is essential for liquid crystal displays for television monitors to lively display the color of human skin because of the nature of images to be displayed on such displays. For this reason, to improve such characteristics as contrast and halftone color reproducibility is a particularly significant problem in liquid crystal displays that are used as television monitors.
As for contrast, many material manufacturers have developed high-contrast materials, and contrast comparable to that of CRTs competitive with LCDs has come to be obtained.
As for halftone color reproducibility, on the other hand, color shift (discrepancy between the center coordinate of the chromaticity coordinates at the display of white color (the coordinate of white color) and that of the chromaticity coordinates at the display of black color (the coordinate of black color)) occurs on a conventional liquid crystal display when the color on the liquid crystal display is changed stepwise from white to black, so that the liquid crystal display has been poor in halftone color reproducibility.
The color hue, depolarizability, etc. of a color filter incorporated in the liquid crystal display is considered to be the main cause of the above problem. Paying attention not to the total contrast of a color filter but to the individual contrasts of red, green, and blue color patterns in a color filter, Japanese Laid-Open Patent Publication No. 2001-194658, for example, proposes a method of making the contrasts of the color patterns closer.
However, according to the inventors' knowledge, the method described in Japanese Laid-Open Patent Publication No. 2001-194658 cannot fully eliminate the discrepancy between the color characteristics at the display of white color and those at the display of black color, and rather worsens halftone color reproducibility.